Transcript 2 1) 2 v 1 = v 2 2) 2 v 1 = v 2 3) 4 v 1 = v 2 4) v 1 = v 2 5) 8 v 1 = v 2 3

1
By what factor does the
1) no change at all
kinetic energy of a car
2) factor of 3
change when its speed
3) factor of 6
is tripled?
4) factor of 9
5) factor of 12
2
Car #1 has twice the mass of
1) 2 v1 = v2
car #2, but they both have the
2)  2 v1 = v2
same kinetic energy. How do
3) 4 v1 = v2
their speeds compare?
4) v1 = v2
5) 8 v1 = v2
3
Two stones, one twice the
mass of the other, are dropped
from a cliff. Just before hitting
the ground, what is the kinetic
energy of the heavy stone
compared to the light one?
1) quarter as much
2) half as much
3) the same
4) twice as much
5) four times as much
4
1) quarter as much
In the previous question, just
before hitting the ground, what is
the final speed of the heavy stone
compared to the light one?
2) half as much
3) the same
4) twice as much
5) four times as much
5
A child on a skateboard is
moving at a speed of 2 m/s.
After a force acts on the child,
her speed is 3 m/s. What can
you say about the work done by
the external force on the child?
1) positive work was done
2) negative work was done
3) zero work was done
6
If a car traveling 60 km/hr can
brake to a stop within 20 m, what
is its stopping distance if it is
traveling 120 km/hr? Assume
that the braking force is the
same in both cases.
1) 20 m
2) 30 m
3) 40 m
4) 60 m
5) 80 m
7
A car starts from rest and accelerates to
30 mph. Later, it gets on a highway and
1) 0  30 mph
accelerates to 60 mph. Which takes more
2) 30  60 mph
energy, the 030 mph, or the 3060 mph?
3) both the same
8
The work W0 accelerates a car from
1) 2 W0
0 to 50 km/hr. How much work is
2) 3 W0
needed to accelerate the car from
3) 6 W0
50 km/hr to 150 km/hr?
4) 8 W0
5) 9 W0
9
Two blocks of mass m1 and m2 (m1 > m2)
1) m1
slide on a frictionless floor and have the
2) m2
same kinetic energy when they hit a long
3) they will go the
rough stretch (m > 0), which slows them
same distance
down to a stop. Which one goes farther?
m1
m2
10
A golfer making a putt gives the ball an initial
velocity of v0, but he has badly misjudged the
putt, and the ball only travels one-quarter of
the distance to the hole. If the resistance force
due to the grass is constant, what speed
should he have given the ball (from its original
position) in order to make it into the hole?
1) 2 v0
2) 3 v0
3) 4 v0
4) 8 v0
5) 16 v0
11
Is it possible for the
1) yes
kinetic energy of an
2) no
object to be negative?
12
Is it possible for the
1) yes
gravitational potential
2) no
energy of an object to
be negative?
13
You and your friend both solve a
problem involving a skier going
down a slope, starting from rest.
The two of you have chosen
different levels for y = 0 in this
problem. Which of the following
quantities will you and your friend
agree on?
A) skier’s PE
B) skier’s change in PE
1) only B
2) only C
3) A, B, and C
4) only A and C
5) only B and C
C) skier’s final KE
14
Two paths lead to the top of a big
hill. One is steep and direct, while
the other is twice as long but less
steep. How much more potential
energy would you gain if you take
the longer path?
1) the same
2) twice as much
3) four times as much
4) half as much
5) you gain no PE in either
case
15
How does the work required to
1) same amount of work
stretch a spring 2 cm compare
2) twice the work
with the work required to
3) 4 times the work
stretch it 1 cm?
4) 8 times the work
16
A mass attached to a vertical
spring causes the spring to
stretch and the mass to
move downwards. What can
you say about the spring’s
potential energy (PEs) and
the gravitational potential
energy (PEg) of the mass?
1) both PEs and PEg decrease
2) PEs increases and PEg decreases
3) both PEs and PEg increase
4) PEs decreases and PEg increases
5) PEs increases and PEg is constant
17
Three balls of equal mass start from rest and roll down different
ramps. All ramps have the same height. Which ball has the
greater speed at the bottom of its ramp?
4) same speed
for all balls
1
2
3
18
A truck, initially at rest, rolls
down a frictionless hill and
attains a speed of 20 m/s at the
bottom. To achieve a speed of
40 m/s at the bottom, how many
times higher must the hill be?
1) half the height
2) the same height
3)  2 times the height
4) twice the height
5) four times the height
19
A box sliding on a frictionless flat
surface runs into a fixed spring,
which compresses a distance x to
stop the box. If the initial speed
of the box were doubled, how
much would the spring compress
in this case?
1) half as much
2) the same amount
3)  2 times as much
4) twice as much
5) four times as much
x
20
Paul and Kathleen start from rest at
1) Paul
the same time on frictionless water
2) Kathleen
slides with different shapes. At the
bottom, whose velocity is greater?
3) both the same
21
You see a leaf falling to the ground
with constant speed. When you
first notice it, the leaf has initial
total energy PEi + KEi. You watch
the leaf until just before it hits the
ground, at which point it has final
total energy PEf + KEf. How do
these total energies compare?
1) PEi + KEi > PEf + KEf
2) PEi + KEi = PEf + KEf
3) PEi + KEi < PEf + KEf
4) impossible to tell from
the information provided
23
Mike applied 10 N of force over 3 m
in 10 seconds. Joe applied the
same force over the same distance
in 1 minute. Who did more work?
1) Mike
2) Joe
3) both did the same work
24
Mike performed 5 J of work in
1) Mike produced more power
10 secs. Joe did 3 J of work
2) Joe produced more power
in 5 secs. Who produced the
3) both produced the same
greater power?
amount of power
25
Engine #1 produces twice the
power of engine #2. Can we
conclude that engine #1 does
twice as much work as engine #2?
1) yes
2) no
26
When you pay the electric company
by the kilowatt-hour, what are you
actually paying for?
1) energy
2) power
3) current
4) voltage
5) none of the above
27
1) hair dryer
Which contributes more to the
cost of your electric bill each
month, a 1500-Watt hair dryer
or a 600-Watt microwave oven?
2) microwave oven
3) both contribute equally
4) depends upon what you
cook in the oven
5) depends upon how long
each one is on
600 W
1500 W